This invention relates to endoscopes which use optical fibers to provide illumination.
Endoscopes are widely used to inspect regions of the body (e.g., joint spaces) through a small puncture wound. Typically, the endoscope includes an elongated insertion tube equipped with a set of optical fibers which extend from a proximal handle, through the insertion tube to the distal viewing tip of the endoscope. A cable that rigidly attaches to the handle (e.g., at a post on the side of the handle) carries light from an external light source to the proximal end of the optical fibers, and the light is transmitted through the optical fibers to the distal viewing end, where the light is emitted to illuminate the region under inspection.
Received light representing an optical image of the body region is collected by a lens assembly mounted in the distal viewing end and is passed to, e.g., a solid-state image pickup device (such as a charge-coupled-device, or CCD). The CCD converts the received optical image to electrical signals that are processed for viewing on a display.
Some endoscopes have a direction of view (i.e., the direction along which the endoscope emits and receives light) along the longitudinal axis of the insertion tube. The distal viewing ends of other endoscopes are constructed to provide an off-axis direction of view (e.g., at 30.degree. or at 70.degree.). The insertion tube of the latter type of endoscope is often rotatable with respect to the handle to allow the user to view different areas without requiring that the entire endoscope be rotated.